The invention relates generally to biocidal ionic solutions and more particularly to apparatus for producing metallic electrolytes for killing moss.
In very moist climates the growth of moss on rooftops, particularly their shaded portions, is a problem. Such moss is unsightly, does not allow the roof to dry properly, and can cause rotting of wood shingles and cracking of composition shingles. This permits water leakage which can damage the support structure of the roof, the ceiling insulation and other ceiling materials. Such damage is very expensive to repair. Consequently, it is desirable to kill moss growing on rooftops and prevent its return.
Manual removal of moss from rooftops is difficult, dangerous and provides only a temporary solution to the problem. The moss regrows within a few weeks from spores remaining beneath the shingles.
Attempts have been made to control moss growth chemically. Ions of certain metallic elements, such as lead, zinc or copper, are known to have biocidal characteristics. At least one such metal, copper, has been used to combat moss, but without great success. For example, nailing a flat strip of copper to a roof has been tried, but has proven unsatisfactory because it can take many months before any reduction in moss occurs. Powdered copper compounds, such as copper sulfate powder sprinkled on the roof, act more quickly than the copper strip, but usually wash off within one month and thus, require frequent reapplications. S. L. Rapaport has previously proposed, in U.S. Pat. No. 3,479,130, mounting flat bimetallic strips horizontally along a rooftop to inhibit microbial or fungal growths which darken rooftops in semitropical and tropical climates. Rapaport discloses the use of two metals, such as copper and lead, between which an electrolytic action results when rainwater contacts the metals. Such action dissolves ions of the metals into the water to create a solution which kills the microbes and fungus. To obtain adequate coverage of a rooftop multiple strips are used, such strips being vertically spaced four to ten shingles apart.
However, installing multiple strips is time consuming and results in a aesthetically unappealing horizontally striped appearance of the roof. Rapaport's subsequent proposal, in U.S. Pat. No. 3,494,727, to imbed chips of ion-producing metal into the surface of roofing material meets the latter objection, but would require re-roofing existing buildings at substantial expense, not to mention the increased cost of producing such roofing material.
It would be preferable to have a means for killing moss on rooftops which is inexpensive, easy to apply, fast-acting, long-lasting and not aesthetically unappealing.